OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Briggs & Stratton OHV intek 60

Hello,
I have stripped and done some cleaning of this mower.
It came from a farm and the chickens have been roosting all over it.
Engine is turning freely.
Oil was contaminated with some water.
Air filter was still in place.
No compression, valve is not moving on intake side.
The base looks like a Husqvarna to me ??
It could be a good engine so I will strip it and see what it is like inside.

Here is the Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/flmtxLX-nfBhU7y.pdf

Here is the Illustrated Parts List:
http://bsintek.basco.com/BriggsDocumentDisplay/18jnxFXCnfBhU7y.pdf

The small Inteks (unlike the large Inteks) seem to have a positive reputation - especially the 850, which seems to be widely worshipped. I haven't heard of the 60 previously - it is one of the earliest of the small Briggs OHV engines, and is out of production.

At this point I haven't laid hands on a small Intek and will be interested in your reports on it. It should certainly have some potential.

Mark, I cant be 100% sure but I am pretty sure the base is an electrolux (It came branded as Flymo (white/ silver base) and Weedeater I believe. Their might be others which I havent seen before.

As always keep your photo's and comments coming. I do like your threads.

I have included a photo of a weedeater model I recently bought back to life to explain what type of base I think yours is.. I love the older briggs engines.



Happy to be corrected if Im wrong.

pete

Thanks for info Grumpy & Jaffa,
Have done a bit more cleaning before pulling it apart.

This one has a plastic fan on the flywheel that has been broken into many pieces.

Rocker cover & plate behind it were leaking, so this has contributed to all the cooling fins being totally blocked.

The valve has freed itself up and I can now feel good compression,

Sounds promising, Mark. Your reports on everything that is wrong with it will be useful - I don't recall we've ever had a report on the condition of an old small Intek.

Just to elaborate on Jaffa's comment re: the base, Yes, flymo, husky, electolux weedeater and possibly one other that doesn't come to mind right now shared this base. Your one is the later one, note the ribs on the front and is a 19' cut and not the usual 18" version like Jaffa's.
That's my 2 cents, keep the updates on the intek coming.

A bit more info on this mower.

Yes bigted, I measured the base, it is indeed 19".
The output shaft is 1"
It has a cast iron sleeve in the bore. (checked with a magnet)
The bore is discoloured/stained but looks and feels good.
Also noticed on the cowl sticker "Diamond edge" which doesn't mean a lot to me.


All is looking OK, next I will rinse the engine out with fuel.
Lap the valves.
Cut some gaskets.
Reassemble the head.
Give the carburettor some attention.





cheers

As far as I can make out, the term "Diamond Edge" was only applied to the 60 series (i.e. 190 cc Intek) engines. There is some suggestion that "Edge" related to the 190 series specifically, and "Diamond" indicated a cast iron cylinder liner. Note that in the Inteks with model numbers beginning with 8, there are both cast iron and aluminium bores, depending on model. The advertising people, in their usual fashion, call the aluminium bore models "Kool-Bore".

If you open the crankcase Mark, I would be very interested in the camshaft, especially the decompressor mechanism. As far as I can tell from the manual, it uses the same decompressor as the bigger Inteks and the Vanguards - a mechanism which seems to lack long term durability. Some detailed pictures would be useful to us all.

Grumpy, I felt for the action of decompressor before pulling it apart, I didn't feel any bump in the valves.

Normally don't have a problem, but the blade plate boss just wont move.
I'll keep at it.
Thanks

At this stage you'll have removed more blade plate bosses than I have Mark, so you obviously know how it has to be done.

If you don't get the decompressor working, your starter won't last long, and it will probably kick back - possibly to a dangerous extent. AFAIK all of the OHV engines have 8:1 compression and at least 20 degrees of ignition advance. On a 190 cc engine, that is not to be taken lightly.

Funnily enough the starter rope is broken.

My approach to finally remove the boss was to soak it, leave it under tension and when ever I walk past it give it a tap with a hammer and retention the bolts and leave it again.
Once it started to move, I went back to my 2 legged puller, it still fought me all the way, really have to be patient.
Don't want to strip the centre bolt, so wind him all the way home.


So I take it that this is the decompressor mechanism below.

I imagine it is meant to be held against the lobe in some way and interact with it as it rotates. I will play wit it and try to work it out.

Here is the picture from the manual:



Yours seems to have a broken return spring, but I can't understand the detail of it. Can you give us some more pictures of it please? In essence, yours is actually quite different from the only one shown in the manual, so we need to get to the bottom of how it works.

Yes, return spring was broken.
I have removed and reshaped it to work again.


My understanding of how it works, so far........ is
Would appreciate other opinions.

During starting it is in the rest position as above, notice the tang is proud of the exhaust lobe (rear).

This tang pushes on the exhaust lifter to bump the exhaust valve during starting.
As below


Once the engine is running does centrifugal force act against the spring to lift it above the lifter??? I was going to put the cam shaft inside a drill chuck and run it to see if that happens. It makes sense to me, as then engine would have full compression at speed.

Delete this post if I am way off the mark here.

As another example see below camshaft for a Quantum engine. (the tang is broken or worn on this one)

It is far cruder than I expected, Mark, and may be a lot less reliable than the Honda one, shown here:


I'll attempt to explain how it works using this mark-up of the above picture:


If you look at the green oval you'll see a spot-welded weight on a long lever arm that reaches nearly the whole way around the timing gear. The lever's pivot is on the right, in the purple oval. Its return spring is in the blue oval. So, above about 600 rpm that lever arm lifts away from the center of the camshaft.

Now look at the orange and yellow ovals. A pressed steel auxiliary cam, pivoted in the yellow oval, is operated by a clevis arrangement in the orange oval, so that when the lever arm is in the rest position (engine not running), the auxiliary cam is in its clockwise position, and a rather neat cam (at the right-hand edge of the yellow oval) is in position to bump the tappet halfway through the compression stroke.

Here is another view of the same decompressor, this time in the "running" position. Note the position of the auxiliary cam, in the red oval:



This particular camshaft is from a GXV120, but they are much the same on the other small Hondas.

Let's look at your Intek 60 mechanism, marked up with colourful ovals:


The pivot of the decompressor auxiliary cam is in the red oval. Imagine the camshaft spinning rapidly: the side of the aux cam in the orange oval is some distance radially from the center of the camshaft, and the aux cam's pivot, so centrifugal force will tend to push it outward. The other side of the aux cam, in the yellow oval, has almost no radial distance from the pivot and camshaft centerline, so it generates very little centrifugal force. However as soon as the orange oval part pulls outward, the yellow oval part begins to be spaced out from the center and generates its own centrifugal force, aiding the orange oval part. Hence the decompressor holds in until the speed rises somewhat, but as soon as it starts to move, it suddenly snaps fully outward.

I dislike this mechanism for several reasons, one being that it uses the sharp edge of a very thin steel stamping as a cam (it will obviously wear away rather quickly, as even the rather better one on the larger Inteks and Vanguards does, necessitating camshaft replacement), it has an exceptionally tin-pot pivot, and its hairpin-type spring is blatantly a piece of rubbish.

My view of the whole setup can be summarised in this way: I've had a couple of Honda GXV120s that had been tortured abominably over many years until they were worn to uselessness, but their decompressors still worked perfectly and showed no signs of wear.

Thanks very much for that Grumpy
I put the Quantum cam shaft in my battery drill and the decompressor throws out at quite a low drill speed.
I am satisfied now with how this set up works and it will help me fault find in the future.

I now also under stand why larger ride on inteks don't start when this mechanism fails.

My spring repair has failed as it will not throw out at all, at full drill speed.
Loosing internet connection now for the day.
Cheers

I think that kind of spring will have a very different "rate" (force versus movement characteristic) when it is shortened, Mark. That is probably why it will not throw out now that you have reshaped it, after it had broken.

Some of the older large Inteks lose their decompressors due to wear on the working edge of the stamped steel cam. They first become very sensitive to tappet clearance, then as wear continues, they will not decompress even when the tappet is correctly adjusted. At that point the camshaft has to be replaced.

I found an image of how the spring is meant to be held in place.


I have replaced this spring with the one I have off the Quantum camshaft.

Few pic's showing the condition of the engine.

Hi Mark,
The engine has cleaned up extremely well and looks to be in great condition.
I hope that the replacement spring will work successfully for you....Have you given it the test will the drill yet?

G'day Darryl,
With regards to the spring, it is not the correct spring.
I have doctored it to suit, I know the consequences if it doesn't work.
I tested it with the drill and it throws out at a similar speed to the quantum one I had as a sample.
I put a bit of tape around the camshaft to protect it from the chuck jaws.
Yes, wear is minimal on the piston, bearings and crank pin.
The bore looked OK to me so I didn't hone it in the end.

All carbon removed and lapped the valves which were not that bad.




Will do some assembly today and check in again tomorrow.

Hello, just to update.
Have repaired the plastic fan.



Here are some specifications from the manual


Started reassembly

I don't know how reliable that fan repair will be, but time will tell. It will be interesting to hear how the engine performs.

Hello, I have started this engine and it isn't running right.
I took a video of it, but it is 40Mb.

Exhaust is emitting not blue or black smoke but white puffs of smoke.
Spitting through the carby at times.
Vibrating due to running out of balance.

After assessing it, changing valve clearances, I have pulled it down again and removed the decompressor completely.
I have it all back together and sealed up again.
I wiil try it again today.
There is quite a bit of compression when starting it now, but not unreasonable.
Like starting a Victa power torque with the decompressor blocked off with a spark plug.



If the engine runs well, I will order a new camshaft and fan.
Some spark plug specs for this engine: Champion RC12YC, BS part no. 499608, clearance .020

I have had this engine running this morning, symptoms are the same, so the decompressor was fine after all.
I am going to clean the carburettor again, which I thought was pretty good.

I cleaned it as per this link below:
http://outdoorpowerinfo.com/repairs/briggs_carb_790120.asp

Cheers

It sounds as if the mixture could be unstable, due to an intermittent air leak or carburetor fault, or a leaking valve or head gasket. You'll need to go through all that again.

If you worked on these engines regularly, it would be useful to keep a "comparison carburetor" that was known to be good.

Thanks, I have rechecked all the clearances and after adjusting the armature air gap down to 0.008" it runs a lot better.
This clearance is a lot smaller than my usual visitors card.
So, bit of a lesson leant there to actually look in the manual for the correct clearance and check it with feeler gauge.
I also cleaned carb again and ensured all the inlet gaskets were sealed.
I have tried a few different spark plugs as well, to try and improve how it runs.

Engine is running ok, still has a intermittent pop from exhaust and a bit of white smoke from exhaust.
I haven't done any mowing with it yet. I will report back when I do.

I have a question about how engine oil finds its way under the rocker cover and does it actually lubricate the rockers. Its not flooded with oil. Question might sound strange.

Usually the oil just slops around between the sump and the rocker cover depending on the slope of the ground. There should be a drain through the lowest part of the head, with a matching hole in the head gasket, to ensure that no oil is trapped in the rocker cover. I've put a yellow oval around the drain hole in your model's head gasket (P/N 697230):


If you put the head gasket on upside down, you'll make a real mess of the drainage system.

The pops in the muffler suggest that the exhaust valve is leaking, or the spark plug is faulty, or either the valve timing or ignition timing is wrong. Coupled with the fact that it is slowly improving, and it had apparently been unused for quite a while before you got it, my first bet would be leaking valves. This is usually due either to them not seating properly, or (perhaps more likely) sticking in the guide just before they close. It is a problem that needs to be fixed.

Also, with regard to your issues with the coil-to-flywheel gap, I suspect you were following a red herring. Refer to this Briggs FAQ:
http://www.briggsandstratton.com/us/en/support/faqs/ignition-system-theory-and-testing

In particular, consider this part of the answer:

"An armature air gap that is too wide will prevent spark. Not true. Well, sort of not true. Briggs & Stratton air gaps cannot be made too wide to prevent spark providing the coil is healthy and the engine is spun over fast enough. A wide air gap, say .030" will ever so slightly retard the ignition timing as the magnetic field takes longer to build within the coil windings."

Thanks Grumpy,
I will revisit the valves, yes, I think maybe valve is sticking in the guide.
Not much to mow here, so I will give it a good run at some point.

I've got the idea now, with how oil enters the rocker area.
This head doesn't have that hole, the holes are for locator pins, so it must come down the push rod tunnel and then the hole in the bottom of the plate pictured. Which I didn't notice until your explanation.

If it doesn't leak, or collect sludge in the head or rocker cover, I guess it works well enough without the drain hole then. I'd like to say that Briggs wouldn't have deleted the drain unless it wasn't needed, but I no longer have that much confidence in Briggs' design team, following some of their Intek exploits.

Hello,

I ran this engine again, it ran great until it warmed up. the symptoms then were:
#missing at times.
#occasional spat through the carb; and
#white/light grey smoke at times from exhaust that seemed to come in waves.

After pulling it down, the intake valve stem still had residue on it, so cleaned it off with an oily scourer pad.
I am confident the valve seats are good.
Reassembled them with assembly grease on the valve stems.
I'll start it up today and fingers crossed it will be ok.
---------------------
While it was apart I investigated how the oil gets in and drains from the rocker cover area.


You can actually see the decompressor through the oil entry hole, so you could inspect for a broken spring through this hole without removing the bottom plate.

Also, a theory, does the decompressor have a secondary role of throwing oil into this hole, once it flattens out at speed?
Still a bit unsure of how all of the components under the rockers get oiled.

I cant see inside the engine when its running, but imagine the oil flicker with the addition of the pressure changes inside, creates an oil mist and this area under the rockers is oiled by a mist of oil?